Cases reported "Aphasia"

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1/152. A case of mixed transcortical aphasia with intact naming.

    Altholgh Lichtheim recognized that Wernicke's 'reflex arch' (primary auditory area, to Wernicke's area, to Broca's area, to primary motor area) was important for repetition, he recognized that other areas of the brain (for example, area of concepts or semantic area) must be important in comprehension and voluntary speech. He suggested that Wernicke's area (phonemic area) not only projected to Broca's area (as Wernicke suggested) but that it also projected to the area of concepts. A lesion of this latter pathway or in the area of concepts would produce a syndrome where repetition was intact but comprehension was impaired (e.g. transcortical sensory aphasia). Lichtheim also thought that the area of concepts projected directly to Broca's area and that voluntary speech was mediated by this pathway. Although Lichtheim's model could explain the mechanism underlying transcortical aphasia, his schema could not explain anomic aphasia. Unlike Lichtheim's schema, Kussmaul's schema suggested that the area of concepts projects back to Wernicke's area before projecting to Broca's area. With this schema, a patient with a hypothetical lesion which interrupted the pathway from the area of concepts to Wernicke's area (but did not interrupt the pathway from Wernicke's area to the area of concepts) should be anomic, with normal comprehension and repetition. In order for this latter schema to be plausible there should also be a lesion which interrupts the pathway from Wernicke's area to the area of concepts but does not interrupt the pathway which goes from the area of concepts to Wernicke's area. A patient with this hypothetical lesion should comprehend poorly; however, in spite of poor comprehension, naming and repetition should be intact. We report a patient who demonstrates poor comprehension with intact naming and repetition. This patient could also read aloud but could not comprehend written language. Not only could this patient name objects but he could demonstrate their use. These observations suggest that comprehension of written language is mediated by a different pathway than the recognition of visually presented objects.
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ranking = 1
keywords = visual
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2/152. Cross-modal priming and explicit memory in patients with verbal production deficits.

    Implicit memory is often thought to reflect an influence of past experience on perceptual processes, yet priming effects are found when the perceptual format of stimuli changes between study and test episodes. Such cross-modal priming effects have been hypothesized to depend upon stimulus recoding processes whereby a stimulus presented in one modality is converted to other perceptual formats. The present research examined recoding accounts of cross-modal priming by testing patients with verbal production deficits that presumably impair the conversion of visual words into auditory/phonological forms. The patients showed normal priming in a visual stem completion task following visual study (Experiment 1), but showed impairments following auditory study in both implicit (Experiment 2) and explicit (Experiment 3) stem completion. The results are consistent with the hypothesis that verbal production processes contribute to the recoding of visual stimuli and support cross-modal priming. The results also indicate that shared processes contribute to both explicit memory and cross-modal implicit memory.
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ranking = 4
keywords = visual
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3/152. Conduction aphasia elicited by stimulation of the left posterior superior temporal gyrus.

    OBJECTIVE: Disruption of fascicular tracts that connect Wernicke's to Broca's areas is the classic mechanism of conduction aphasia. Later work has emphasised cortical mechanisms. methods: To determine the distribution of language on dominant cortex, electrical cortical stimulation was performed using implanted subdural electrodes during brain mapping before epilepsy surgery. RESULTS: A transient, isolated deficit in repetition was elicited with stimulation of the posterior portion of the dominant superior temporal gyrus. CONCLUSION: This finding suggests that cortical dysfunction, not just white matter disruption, can induce conduction aphasia.
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ranking = 9.2087907109354
keywords = cortex
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4/152. Contributions of prefrontal cortex to recognition memory: electrophysiological and behavioral evidence.

    To clarify the involvement of prefrontal cortex in episodic memory, behavioral and event-related potential (ERP) measures of recognition were examined in patients with dorsolateral prefrontal lesions. In controls, recognition accuracy and the ERP old-new effect declined with increasing retention intervals. Although frontal patients showed a higher false-alarm rate to new words, their hit rate to old words and ERP old-new effect were intact, suggesting that recognition processes were not fundamentally altered by prefrontal damage. The opposite behavioral pattern was observed in patients with hippocampal lesions: a normal false-alarm rate and a precipitous decline in hit rate at long lags. The intact ERP effect and the change in response bias during recognition suggest that frontal patients exhibited a deficit in strategic processing or postretrieval monitoring, in contrast to the more purely mnemonic deficit shown by hippocampal patients.
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ranking = 46.043953554677
keywords = cortex
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5/152. Partial seizure with aphasic speech arrest caused by watching a popular animated TV program.

    On the evening of December 16, 1997, about 700 children across japan were hospitalized because of convulsive seizures or vomiting experienced while watching a popular animated TV program that included blue and red stimuli that alternated at 12 flashes per second. In one case, an 11-year-old girl developed a hallucination in the right visual field and a subsequent cramp on the right side of her face, with aphasic speech arrest. She had no history of seizures. Her electroencephalogram (EEG) showed normal background activity and no epileptiform discharges. Intermittent photic stimulation provoked a photoparoxysmal response. Her main clinical manifestation was a TV-induced left occipital lobe seizure spreading toward the left inferior frontal lobe. This suggested a functional link from the occipital lobe to the frontal operculum.
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ranking = 1
keywords = visual
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6/152. Subcortical mechanisms in language: lexical-semantic mechanisms and the thalamus.

    Four previously published cases of dominant thalamic lesion in which the author has participated are reviewed to gain a better understanding of thalamic participation in lexical-semantic functions. Naming deficits in two cases support Nadeau and Crosson's (1997) hypothesis of a selective engagement mechanism involving the frontal lobes, inferior thalamic peduncle, nucleus reticularis, and other thalamic nuclei, possibly the centromedian nucleus. This mechanism selectively engages those cortical areas required to perform a cognitive task, while maintaining other areas in a state of relative disengagement. Deficits in selective engagement disproportionately affect lexical retrieval based on semantic input, as opposed to lexical and sublexical processes, because the former is more dependent upon this attentional system. The concept of selective engagement is also useful in understanding thalamic participation in working memory, as supported by data from one recent functional neuroimaging study. Other processes also may be compromised in more posterior thalamic lesions which damage the pulvinar but not other components of this selective engagement system. A third case with aphasia after a more superior and posterior thalamic lesion also had oral reading errors similar to those in neglect dyslexia. The pattern of deficits suggested a visual processing problem in the early stages of reading. The fourth case had a category-specific naming deficit after posterior thalamic lesion. Taken together, the latter two cases indicate that the nature of language functions in more posterior regions of the dominant thalamus depends upon the cortical connectivity of the thalamic region. Together, findings from the four cases suggest that thalamic nuclei and systems are involved in multiple processes which directly or indirectly support cortical language functions.
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ranking = 1
keywords = visual
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7/152. functional neuroimaging of speech perception in six normal and two aphasic subjects.

    This positron emission tomography study used a correlational design to investigate neural activity during speech perception in six normal subjects and two aphasic patients. The normal subjects listened either to speech or to signal-correlated noise equivalents; the latter were nonspeech stimuli, similar to speech in complexity but not perceived as speechlike. Regions common to the auditory processing of both types of stimuli were dissociated from those specific to spoken words. Increasing rates of presentation of both speech and nonspeech correlated with cerebral activity in bilateral transverse gyri and adjacent superior temporal cortex. Correlations specific to speech stimuli were located more anteriorly in both superior temporal sulci. The only asymmetry in normal subjects was a left lateralized response to speech in the posterior superior temporal sulcus, corresponding closely to structural asymmetry on the subjects' magnetic resonance images. Two patients, who had left temporal infarction but performed well on single word comprehension tasks, were also scanned while listening to speech. These cases showed right superior temporal activity correlating with increasing rates of hearing speech, but no significant left temporal activation. These findings together suggest that the dorsolateral temporal cortex of both hemispheres can be involved in prelexical processing of speech.
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ranking = 18.417581421871
keywords = cortex
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8/152. Global aphasia: an innovative assessment approach.

    OBJECTIVE: To provide an alternative language comprehension assessment strategy for patients unable to be tested with traditional verbally/behaviorally based methods. DESIGN: Event-related brain potentials were recorded from three midline scalp locations to visually and aurally computer-presented sentences, 50% of which were semantically appropriate and 50% semantically incongruous. SETTING: A rehabilitation hospital. PATIENT: A 21-year-old man with a traumatic brain injury. RESULTS: The patient exhibited brain response patterns to aurally presented congruous and incongruous sentences indicative of intact semantic processing capabilities. These findings resulted in reinstatement of individualized rehabilitative intervention, with a successful outcome. CONCLUSIONS: This innovative technique provides new opportunities for assessing intellectual function in noncommunicative patients who were patients previously unable to be tested.
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ranking = 1
keywords = visual
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9/152. Rapidly progressive aphasia and motor neuron disease: a clinical, radiological, and pathological study of an autopsy case with circumscribed lobar atrophy.

    This report concerns an autopsy case of rapidly progressive aphasia and motor neuron disease. The patient was a Japanese woman who was 75 years old at the time of death. The family history did not reveal hereditary burden. She developed language disturbances and difficulty in swallowing at age 74. Neurological examination 1 month after the disease onset revealed motor aphasia without dementia and bulbar sign, followed by muscle weakness of the four extremities. Neuroradiological examination revealed progressive atrophy of the anterior part of the left temporal lobe. She died of respiratory difficulty 10 months after the disease onset. Macroscopically, neuropathological examination showed circumscribed atrophy of the left perisylvian region and, histologically, neuronal loss in the cerebral cortex, including the primary motor area, substantia nigra, brain stem motor nuclei, and anterior horns of the spinal cord, in addition to obvious degeneration of the pyramidal tracts and presence of Bunina bodies. ubiquitin-immunoreactive neuronal inclusions were present in the hippocampal dentate granular cells and frontotemporal cortical layer II neurons. Based on these clinicopathological findings and a review of the literature, we concluded that our case is the first reported case of amyotrophic lateral sclerosis with dementia that clinically showed rapidly progressive aphasia.
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ranking = 9.2087907109354
keywords = cortex
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10/152. Visual paralexias in a Spanish-speaking patient with acquired dyslexia: a consequence of visual and semantic impairments?

    We report the case of a Spanish patient SC who misread 55 per cent of the single words shown to her. SC's reading accuracy was affected by word imageability and frequency. Nonword reading was very poor. The majority of SC's errors to real-word targets bore a close visual similarity to the items that elicited them, but there was no indication of an effect of serial position on the probability that a letter from a target word would be incorporated into the error made to that word. SC made some visual errors in object naming and also showed evidence of a general semantic impairment. We consider the similarity between SC and patient AB reported by Lambon Ralph and Ellis (1997), and suggest that the very high levels of visual errors shown by these two patients may reflect a combination of visual and semantic impairments.
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ranking = 8
keywords = visual
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